#main_container {
    width: 100%;
    height: 100%;
}
html, body {
    width: 100%;
    height: 100%;
}

button{
    width: 80px;
    height: 60px;
    position: absolute;
    right: 0;
}

#placeholder {
    position: absolute;  width: 800px;  height: 400px;  right: 0; display: none;
}
